JPH0380432A - Method and device for recording and reproducing optical disk - Google Patents

Abstract

PURPOSE:To make signals which are recorded and reproduced equal by recording information on adjacent tracks after delaying it by the time corresponding to the relative position in the circumferential direction of each beam spot of a multibeam and reproducing the information from the tracks. CONSTITUTION:An input circuit 3 converts an input signal 14 corresponding to the number of signals emitted from an optical head 2. A delay circuit 4 respectively delays the plural signals inputted from the circuit 3 by the time corresponding to the deviation of the relative position in the circumferential direction of each beam spot 12. A recording circuit 5 records the information on the track 13 on an optical disk 1 in accordance with the delayed signal inputted from the circuit 4. A reproducing circuit 6 converts the information fetched from the track 13 by plural beams of the head 2 into a reproducing signal. A delay circuit 7 delays the plural signals inputted from the circuit 6 by the time corresponding to the deviation of the relative position in the circumferential direction of each spot 12. An output circuit 8 converts the plural signals from the circuit 7 into an output signal 15. Thus, recording and reproducing are performed from the equal position on the disk 1.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical disc recording/reproducing method and a recording/reproducing apparatus using multi-beams.

<Prior Art> FIG. 6 shows a conventional optical disc recording and reproducing apparatus using multi-beams. The figure is related to Japanese Patent Application Laid-Open No. 117744/1983. That is, as shown in FIG. 6, concentrically adjacent tracks 62 are formed on the optical disc 61, and information is recorded on these tracks 62.

A multi-beam optical head 64 is installed above the optical disc 61, and a plurality of beams are irradiated from this optical head 64 onto each adjacent track 62 of the optical disc 61. Here, the irradiated beam spot 63 has a certain spread and needs to be spaced at a certain interval or more. For this reason, the arrangement direction 65 of the beam spots between adjacent tracks 62 cannot be set in the radial direction of the optical disc 61, but is tilted in the circumferential direction of the optical disc 61.

When recording, first, the arrangement direction 65 of the beam spots is adjusted to align the plurality of beam spots 6 from the optical head 64.
3 to track on adjacent tracks. After that, the light intensity of the beam is changed for each beam spot according to the information to be recorded, and recording is performed on the track 62 by changing the reflectance or the direction of magnetization.

Further, during reproduction, the array direction 65 of the beam spots is adjusted in the same way as during recording so that the plurality of beam spots 63 from the optical head 64 track on adjacent tracks. Thereafter, information is reproduced as a change in the amount of reproduction light or a change in the Kerr rotation angle for each beam spot.

<Problems to be Solved by the Invention> In the conventional optical disc recording and reproducing apparatus described above, recording and reproducing can be performed on multiple tracks at the same time by irradiating the optical disc with a plurality of beams. There is a problem in that the optical disc 61 is tilted in the circumferential direction.

Therefore, if the recording pulse light is applied to each beam spot 63 at the same time, the bit positions to be recorded will be spaced apart in the circumferential direction.

Therefore, it was not possible to record using multi-beam on an optical disc with pre-formatted sectors.

The present invention has been made in view of the above-mentioned prior art,
It is an object of the present invention to provide a method and apparatus capable of recording information using multi-beams on adjacent tracks of an optical disk in a circumferentially aligned manner and reproducing the information.

<m1ll! Means for Solving the Problem> The configuration of the optical disk recording and reproducing method of the present invention that achieves the above object is to irradiate a plurality of beams from a multi-beam optical head onto adjacent tracks on the optical disk, and to set the respective beam spots. In the method of recording and reproducing by positioning the beam spots apart in the circumferential direction, information is recorded on the tracks by the beams with a delay corresponding to the relative positions of the beam spots in the circumferential direction, and the beam spots The information on the track is reproduced by the beam with a delay of a time corresponding to the relative position in the circumferential direction of the track.

Further, the configuration of the optical disk recording/reproducing apparatus of the present invention that achieves the above object is such that a multi-beam optical head irradiates a plurality of beams onto adjacent tracks on the optical disk, and separates each beam spot in the circumferential direction. In a device that records and plays by positioning the
a delay circuit for delaying information recorded on each track by the beam by a time corresponding to the relative position of the beam spot in the local direction; and a delay circuit for delaying information recorded on each track by the beam by a time corresponding to the relative position of the beam spot; The present invention is characterized in that a delay time FRI is provided for delaying by a time corresponding to the relative position in the direction.

Function: When multiple beams from a multi-beam optical head are irradiated onto adjacent tracks on an optical disk and information is recorded by separating each beam spot in the circumferential direction, each beam spot is recorded at the same time. Instead, if the information is recorded with a delay time corresponding to the relative position of the beam spot in the circumferential direction using a delay circuit, the information recorded on each track will be aligned in the circumferential direction.

Conversely, instead of playing back each beam spot at the same time, if you delay playback by a time corresponding to the relative position of the beam spot in the circumferential direction using a delay circuit, each track will be played from the same position in the local direction. That will happen.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an optical disk recording and reproducing apparatus according to an embodiment of the present invention. As shown in the figure, tracks 13 are formed concentrically adjacent to each other on the optical disc 1, and a multi-beam optical head 2 is installed below the optical disc 1. A plurality of beams (three in the figure) are irradiated from this optical head 2 onto adjacent tracks 13 of the optical disc 1. Here, the beam spots 12 have a certain spread and need to be separated by a certain distance or more. Therefore, the beam spots 12 cannot be arranged in the radial direction, but are arranged obliquely in the circumferential direction.

Furthermore, the optical head 2 has an input port #3. Delay time $4. Recording circuit 5. Regeneration circuit 6. A delay circuit 7 and an output circuit 8 are attached.

The input circuit 3 converts one or more input signals 14 according to the number of signals emitted from the optical head 2.

The delay amount Ws4 delays each of the plurality of signals inputted from the input circuit 3 (same as the number of beams emitted from the optical head 2) by a time corresponding to the relative positional deviation of each beam spot 12 in the circumferential direction. It is something. The recording circuit drives the optical head 2 in response to a delayed signal input from the delay circuit 4, and records information on a track 13 on the optical disk using a beam emitted from the optical head 2.

Also, the playback diagram l@6 is the adjacent track 1 of the optical disc.
The information extracted from the optical head 3 by a plurality of beams of the optical head 2 is converted into a digital reproduction signal. The delay amount 67 delays the plurality of signals inputted from the reproducing circuit 6 by a time corresponding to the circumferential relative positional shift of each beam spot 12. The output circuit 8 converts the plurality of signals delayed by the delay amount Ws7 into one or more output signals 15.

According to the present invention having the above configuration, it is possible to perform recording and reproduction using multiple beams from positions aligned in the circumferential direction of the optical disc 1.

First, when recording information, a plurality of signals input from the input circuit 3 are delayed by a time corresponding to the relative positional shift in the circumferential direction of each beam spot 12, so that information is recorded on each track of the optical disc 1. The signals, that is, the information sent can be made uniform in the circumferential direction. Therefore, as shown in FIG.
It can be arranged concentrically, and sectors 21 and 21 can be arranged concentrically.
Can also be recorded on pre-formatted optical discs.

It will be possible to play it.

Furthermore, when reproducing information, the plurality of signals inputted from the reproducing circuit 6 are delayed by a time corresponding to the relative positional shift of each beam spot 12 in the circumferential direction. It is possible to play from positions aligned in the circumferential direction.

Incidentally, the present invention is a CAV whose preformat is concentric (
Not only CLV (constant angular velocity), but also CLV (constant angular velocity), Z
It can also be applied to CAV, etc.

Next, input circuit 3. A specific example of the output circuit 8 will be explained with reference to FIG. 3(a) (bl).

FIG. 3 (al is buffer memory 31. error correction circuit 3
It shows an input circuit 3 consisting of a 22 division circuit and a modulation diagram $34. Here, the input signal 14 to the input @$3 is first stored in the buffer memory 31, and then an FCC (error correction code) is applied to the error correction circuit 32 for error recovery.
A CRC (cyclic code) is added. And split circuit 3
3, it is divided into the number of signal lines according to the number of beams of the optical head,
A modulation circuit 34 applies modulation to each signal and outputs it as an output signal 35 from the input path 3. In addition, as a modulation method, for example, 2/7 pit body recording (P
PM), other 2/7, 1/7゜4/11, 4/15,
8-10. RZ, NRZ, etc. and PWM (bit position notation, PPM.

Combinations such as Ampj (fi width modulation) can be made.

In addition, in FIG. 3 (al), the dividing circuit 33 is shown as an error correction diagram 1s3.
The arrangement in the input circuit can be changed, such as placing the dividing port $33 before the buffer memory 31, before the error correction circuit 32, and after the modulation direction f@34. Also, the buffer memory 31. Error correction circuit 32. It is also possible to transfer one or more of the modulation directions $34 to the recording circuit 5.

On the other hand, FIG. 3tb+ shows the fi adjustment circuit 81. coupling circuit 82,
It shows an output circuit 8 comprising a v14 correction diagram ItI83 and a buffer memory 84.

Here, the input signal 86 to the output circuit 8 is first input to the demodulation diagram l.
581 txyi, and then a combination circuit 82 combines the plurality of inputs. And ECC with error correction @#32
, CRC is used for error recovery processing, stored in the buffer memory 84, and outputted from the output circuit 8 as an output signal 15. In addition, in FIG. 3(b), the connection port #! I82 is placed after the demodulation circuit 81, but the arrangement within the output circuit can be changed, such as placing it before the uL modulation circuit 81, after the error correction diagram $32, and after the buffer memory 84. Also, the demodulation diagram 'Ii! I81. It is also possible to move one or more of the error correction circuit 32 and the buffer memory 84 to the reproduction circuit. Furthermore, although the input circuit 3 and the output circuit 8 are shown separately in FIG. 1, they can be shared in the same circuit, and the delay circuit 4, the delay amount*7p recording circuit 5, and the reproduction circuit 6 can also be used in the same way. .

Note that the configuration of the present invention is not limited to the embodiment shown in FIG. 1, and various embodiments are possible. For example, the second embodiment shown in FIG. 4 has a delay detection interval g89 added to the configuration of FIG. 1.

In this embodiment, signals are inputted from the reproduction cycle i16 to the delay detection circuit 9, the sector marks of the optical disc 1 are detected for each signal, and the time difference for each signal is calculated.

The calculated time difference is determined by the delay amount 'Is4 by the signal line 10.
and is used to correct the amount of delay in the recording signal. The calculated time difference is similarly transmitted to the delay circuit 7 via the signal line 11.
and is used to correct the amount of delay in the reproduced signal.

Therefore, even if the distance between the beam spots of the optical head varies or changes over time, the recording signal of each beam spot
The timing of the reproduced signal can be corrected.

Here, an example is shown in which the sector mark of the optical disc 1 is used to detect the amount of delay, but the clock bit, sync bit, and resync bit.

It can also be detected by data bits.

Above 1. In the second embodiment, as shown in FIG. 2, the sectors 23 are arranged concentrically for each track, but in the incoming direction! ! @3 and output times Ii! ! 8, Figure 5(a)
(b) You can also do it as shown in (c).

In FIG. 5(a), a sector is constructed using four tracks on an optical disk. That is, the cutting tool 42 has four bits 41 in the radial direction and two bits 41 in the circumferential direction.
Each bit 41 is allocated on the medium as a recording bit. Here, the recording bit includes not only a three-dimensional depression but also a change in the direction of magnetization, etc. In this way, even if a defect 43 with a size of several bits occurs in the circumferential direction and radial direction on the optical disk, the defective bits are concentrated in several bytes 42, and as a result,
The number of bytes that result in an error for one defect 43 is reduced, and the number of consecutive bytes that result in an error can be reduced. Although FIG. 5 (al) shows an example in which the cutting tool 42 is configured with four bits 41 in the radial direction and two bits 41 in the circumferential direction, the configuration in each direction can also be changed.

For example, by regularly shifting the byte 52 consisting of eight bits 51 as shown in FIG. It is possible to reduce the number of consecutive bytes 52 that result in an error.

<Effects of the Invention> As explained above, the present invention can make the signals recorded and reproduced by each beam spot uniform in the circumferential direction on the optical disc in recording and reproduction of an optical disc using multi-beams. Recording and playback can also be performed on optical discs with preformatted sectors.

Furthermore, by detecting the position of each beam spot, it is possible to correct the timing of the recording and playback signals for each beam spot. can be done.

In addition, if one byte configuration uses several bits in the track direction, even if defects of several bits occur in the circumferential and radial directions on the optical disk, the defective bits can be concentrated in a few bytes. You can do it. For this reason,
The number of bytes resulting in an error due to one defect is reduced, the number of consecutive bytes resulting in an error can be reduced, and the ECC processing time is also shortened.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an optical disk recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing tracks on the optical disk, FIG. 3 Za) is a block diagram of an input circuit, and FIG.
bl is a block diagram of an output circuit, FIG. 4 is a block diagram of an optical disk recording/reproducing apparatus according to another embodiment of the present invention, and FIG.
a) (b) (CL is an explanatory diagram showing the structure of bytes on an optical disk, and FIG. 6 is an explanatory diagram of conventional multi-beam recording. In the drawings, 1 is an optical disk, 2 is an optical head, and 3 is an explanatory diagram of conventional multi-beam recording. Input circuit, 4.7 is a delay circuit, 5 is a recording circuit, 6 is a playback circuit, 8 is an output circuit, 9 is a delay detection circuit, 10.11 is a signal line, 12 is a beam spot, 13 is a track, 14 is an input 15 is the output signal. Figure 3 (a) Figure 5 (a) Figure 6

Claims (2)

[Claims] (1) In a method of recording and reproducing by respectively irradiating a plurality of beams from a multi-beam optical head onto adjacent tracks on an optical disk and positioning each beam spot apart in the circumferential direction, the circumferential direction of the beam spot is The information on the tracks is recorded by the beams by a time corresponding to the relative position of the beam spot, and the information on the tracks is recorded by the beam by a time corresponding to the relative position of the beam spot in the circumferential direction. A method for recording and reproducing an optical disc, the method comprising: reproducing an optical disc; (2) In a device that performs recording and reproduction by irradiating a plurality of beams from a multi-beam optical head onto adjacent tracks on an optical disk and positioning the respective beam spots apart in the circumferential direction, the beams illuminate the tracks. A delay circuit delays the information recorded on each track by a time corresponding to the relative position of the beam spot in the circumferential direction, and the information reproduced from the track by the beam corresponds to the relative position of the beam spot in the circumferential direction. What is claimed is: 1. An optical disk recording and reproducing device characterized by being provided with a delay circuit that delays the time by the amount of time required.